Meta-analysis for association of TNFA-308(G>A) SNP with vitiligo susceptibility.

Abstract

Vitiligo is an autoimmune progressive skin depigmenting disease. Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine and plays a crucial role in vitiligo development. Since there are conflicting results and consensus is lacking for the association of the TNFA gene -308 G>A polymorphism with vitiligo susceptibility; we performed a meta-analysis of all the available studies to investigate the association of TNFA -308 G>A polymorphism with vitiligo risk. 11 studies involving 2199 vitiligo patients and 3083 controls were included in the meta-analysis. The meta-analysis revealed an increased vitiligo risk with "AA", "GA" and "AA"+"GA" genotypes and 'A' allele in the overall (p=0.006, p=0.003, p=0.001 & p=0.003) and Egyptian populations (p=0.001, p<0.00001, p<0.00001 & p=0.002). Moreover, we found association for "GA" and "AA"+"GA" genotypes in Asian population (p=0.0009 & p=0.005) and for 'A' allele in Asian and middle eastern populations (p=0.04 & p=0.0002). Interestingly the disease activity based analysis revealed significant association for "GA", "AA"+"GA" genotypes and 'A' allele with active vitiligo patients in the North American population (p=0.02). Moreover, we found significant association for "GA", "AA"+"GA" genotypes and 'A' allele with localized vitiligo in overall (p=0.02, p=0.02 & p=0.04) and Asian (p=0.004, p=0.003 & p=0.01) populations. Overall, our meta-analysis suggests the involvement of susceptible 'A' allele with: i) vitiligo susceptibility in overall population and specifically with Asian, Middle Eastern and Egyptian populations; ii) vitiligo disease activity in North American population and iii) localized vitiligo in overall population and specifically in Asian population.